Leakdown plunger

ABSTRACT

The present invention relates to a roller follower, comprising an outer surface, enclosing a first cavity and a second cavity, wherein the first cavity includes a first inner surface configured to house a cylindrical insert, the second cavity includes a second inner surface cylindrically shaped, and at least one of the cavities is fabricated through forging.

FIELD OF THE INVENTION

[0001] This invention relates to bodies for leakdown plungers, and particularly to leakdown plungers used in combustion engines.

BACKGROUND OF THE INVENTION

[0002] Leakdown plungers are known in the art and are used in camshaft internal combustion engines. Leakdown plungers open and close valves that regulate fuel and air intake. As noted in U.S. Pat. No. 6,273,039 to Church, the disclosure of which is hereby incorporated herein by reference, leakdown plungers are typically fabricated through machining. Col. 8, ll. 1-3. However, machining is inefficient, resulting in increased labor and decreased production.

[0003] The present invention is directed to overcoming this and other disadvantages inherent in prior-art lifter bodies.

SUMMARY OF THE INVENTION

[0004] The scope of the present invention is defined solely by the appended claims, and is not affected to any degree by the statements within this summary. Briefly stated, a leakdown plunger, comprising an outer surface, enclosing a first cavity and a second cavity, wherein the first cavity includes a first inner surface configured to house a cylindrical insert, the second cavity includes a second inner surface cylindrically shaped, and at least one of the cavities is fabricated through forging.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIG. 1 depicts a preferred embodiment of a leakdown plunger.

[0006]FIG. 2 depicts a preferred embodiment of a leakdown plunger.

[0007]FIG. 3-a depicts the top view of a preferred embodiment of a leakdown plunger.

[0008]FIG. 3-b depicts the top view of a preferred embodiment of a leakdown plunger.

[0009]FIG. 4 depicts the top view of another preferred embodiment of a leakdown plunger.

[0010]FIG. 5 depicts a second embodiment of a leakdown plunger.

[0011]FIG. 6 depicts a third embodiment of a leakdown plunger.

[0012]FIG. 7 depicts a fourth embodiment of a leakdown plunger.

[0013]FIG. 8 depicts a fifth embodiment of a leakdown plunger.

[0014]FIG. 9 depicts the top view of another preferred embodiment of a leakdown plunger.

[0015]FIG. 10 depicts the top view of another preferred embodiment of a leakdown plunger.

[0016]FIG. 11 depicts a sixth embodiment of a leakdown plunger.

[0017]FIG. 12 depicts a seventh embodiment of a leakdown plunger.

[0018]FIG. 13 depicts an eighth embodiment of a leakdown plunger.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0019] Turning now to the drawings, FIGS. 1, 2, and 3 show a leakdown plunger 10 constituting a preferred embodiment of the present invention. The leakdown plunger 10 is composed of a metal, preferably aluminum. According to one aspect of the present invention, the metal is copper. According to another aspect of the present invention, the metal is iron.

[0020] Those skilled in the art will appreciate that the metal is an alloy. According to one aspect of the present invention, the metal includes ferrous and non-ferrous materials. According to another aspect of the present invention, the metal is a steel. Those skilled in the art will appreciate that steel is in a plurality of formulations and the present invention is intended to encompass all of them. According to one embodiment of the present invention the steel is a low carbon steel. In another embodiment of the present invention, the steel is a medium carbon steel According to yet another embodiment of the present invention, the steel is a high carbon steel.

[0021] Those with skill in the art will also appreciate that the metal is a super alloy. According to one aspect of the present invention, the super alloy is bronze; according to another aspect of the present invention, the super alloy is a high nickel material. According to yet another aspect of the present invention, the leakdown plunger 10 is composed of pearlitic material. According to still another aspect of the present invention, the leakdown plunger 10 is composed of austenitic material. According to another aspect of the present invention, the metal is a ferritic material.

[0022] The body 20 is composed of a plurality of shaft elements. According to one aspect of the present invention, the shaft element is cylindrical in shape. According to another aspect of the present invention, the shaft element is conical in shape. According to yet another aspect of the present invention, the shaft element is hollow.

[0023]FIG. 1 depicts a cross-sectional view of the preferred embodiment of the present invention composed of a plurality of shaft elements. FIG. 1 shows the body, generally designated 20. The body 20 functions to accept a liquid, such as a lubricant and is provided with a first opening 31 and a second opening 32. The first opening 31 functions to accommodate an insert.

[0024] The body 20 of the preferred embodiment is fabricated from a single piece of metal wire or rod and is described herein as a plurality of shaft elements. The body 20 includes a first hollow shaft element 21, a second hollow shaft element 23, and an insert-accommodating shaft element 22. As depicted in FIG. 1, the first hollow shaft element 21 is located adjacent to the insert-accommodating shaft element 22. The insert-accommodating shaft element 22 is located adjacent to the second hollow shaft element 23.

[0025] The body 20 is provided with a plurality of outer surfaces and inner surfaces. FIG. 2 depicts the first opening 31 of an alternative embodiment. The first opening 31 of the embodiment depicted in FIG. 2 is advantageously provided with a chamfered surface 33, however a chamfered surface 33 is not necessary. When used herein in relation to a surface, the term “chamfered” shall mean a surface that is rounded or angled.

[0026] The first opening 31 depicted in FIG. 2 is configured to accommodate an insert. The first opening 31 is shown in FIG. 2 accommodating a valve insert 43. In the embodiment depicted in FIG. 2, the valve insert 43 is shown in an exploded view and includes a generally spherically shaped member 44, a spring 45, and a cap 46. Those skilled in the art will appreciate that valves other than the valve insert 43 shown herein can be used without departing from the scope and spirit of the present invention.

[0027] As shown in FIG. 2, the first opening 31 is provided with an annular surface 35 defining a hole 36. The hole 36 is shaped to accommodate an insert. In the embodiment depicted in FIG. 2, the hole 36 is shaped to accommodate the spherical member 44. The spherical member 44 is configured to operate with the spring 45 and the cap 46. The cap 46 is shaped to at least partially cover the spherical member 44 and the spring 45. The cap is preferably fabricated through stamping. However, the cap may be forged or machined without departing from the scope or spirit of the present invention.

[0028]FIG. 3 shows a cross-sectional view of the embodiment depicted in FIG. 2 in a semi-assembled state. In FIG. 3 the valve insert 43 is shown in a semi-assembled state. As depicted in FIG. 3, a cross-sectional view of a cap spring 47 is shown around the cap. Those skilled in the art will appreciate that the cap spring 47 and the cap 46 are configured to be inserted into the well of another body. According to one aspect of the present invention, the cap spring 47 and the cap 46 are configured to be inserted into the well of a lash adjuster, such as the lash adjuster disclosed in Applicant's “Lash Adjuster Body,” application Ser. No. ______ filed on Oct. 18, 2002, a copy of which is attached hereto, the disclosure of which is incorporated herein by reference. According to another aspect of the present invention, the cap spring 47 and the cap 46 are configured to be inserted into the well of a valve lifter, such as the valve lifter disclosed in Applicant's “Valve Lifter Body,” application Ser. No. ______, filed on Oct. 18, 2002, a copy of which is attached hereto, the disclosure of which is incorporated herein by reference.

[0029] The cap 46 is configured to at least partially depress the spring 45. The spring 45 exerts a force on the spherical member 44. The annular surface 35 is shown with the spherical member 44 partially located within the hole 36.

[0030] Referring now to FIG. 2, the embodiment is provided with an outer surface 80. The outer surface 80 is preferably shaped so that the body can be inserted into a lash adjuster body, such as that disclosed in the inventors' patent application entitled “Lash Adjuster Body,” application Ser. No. ______ filed on Oct. 18, 2002, a copy of which is attached hereto, the disclosure of which is incorporated herein by reference. Depicted in FIG. 2 is a lash adjuster body 90 having an inner surface 91 defining cavity 92. The embodiment of the present invention is depicted in FIG. 2 within the cavity 92 of the lash adjuster body 90. The body 20 of the leakdown plunger is provided with an outer surface 80 that is cylindrically shaped.

[0031]FIG. 4 depicts an alternative embodiment of the present invention and FIG. 4 depicts the second opening 32 of the present invention in greater detail. The second opening 32 is shown with a chamfered surface 34. However, those with skill in the art will appreciate that the second opening 32 may be fabricated without the chamfered surface 34.

[0032] The embodiment depicted in FIG. 4 is provided with a plurality of outer surfaces. The outer surface 80 includes a plurality of surfaces. In the embodiment depicted in FIG. 4, the outer surface 80 includes a cylindrical surface 81, an undercut surface 82, and a conical surface 83. As depicted in FIG. 4, the undercut surface 82 extends from one end of the body 20 and is cylindrically shaped. The diameter of the undercut surface 82 is smaller than the diameter of the cylindrical surface 81.

[0033] The undercut surface 82 is preferably forged through use of an extruding die. Alternatively, the undercut surface 82 is fabricated through machining. Machining the undercut surface 82 is accomplished through use of an infeed centerless grinding machine, such as a Cincinnati grinder. The surface is first heat-treated and then the undercut surface 82 is ground via a grinding wheel. Those skilled in the art will appreciate that additional surfaces can be ground into the outer surface with minor alterations to the grinding wheel.

[0034] Referring again to FIG. 4, the conical surface 83 is located between the cylindrical surface 81 and the undercut surface 82. Those with skill in the art will appreciate that the outer surface 80 can be fabricated without the conical surface 83 so that the cylindrical surface 81 and the undercut surface 82 abut one another.

[0035]FIG. 6 depicts an embodiment of the present invention with a section of the outer surface 80 broken away. The embodiment depicted in FIG. 6 is provided with a first opening 31. As shown in FIG. 6, the outer surface 80 encloses an inner surface 50. The inner surface 50 includes an annular surface 35 that defines a hole 36.

[0036]FIG. 7 depicts a cross-sectional view of an alternative embodiment of the present invention. The body 20 shown in FIG. 7 is provided with an outer surface 80 that includes a plurality of cylindrical and conical surfaces. In the embodiment depicted in FIG. 7, the outer surface 80 includes an outer cylindrical surface 81, an undercut surface 82, and an outer conical surface 83. As depicted in FIG. 7, the undercut surface 82 extends from one end of the body 20 and is cylindrically shaped. The diameter of the undercut surface 82 is smaller than, and preferably concentric relative to, the diameter of the outer cylindrical surface 81. The outer conical surface 83 is located between the outer cylindrical surface 81 and the undercut surface 82. Those with skill in the art will appreciate that the outer surface 80 can be fabricated without the conical surface 83 so that the outer cylindrical surface 81 and the undercut surface 82 abut one another.

[0037]FIG. 8 depicts in greater detail the first opening 31 of the embodiment depicted in FIG. 7. The first opening 31 is configured to accommodate an insert and is preferably provided with a first chamfered surface 33. Those skilled in the art, however, will appreciate that the first chamfered surface 33 is not necessary. As further shown in FIG. 8, the first opening 31 is provided with a first annular surface 35 defining a hole 36.

[0038] The embodiment depicted in FIG. 8 is provided with an outer surface 80 that includes a plurality of surfaces. The outer surface 80 includes a cylindrical surface 81, an undercut surface 82, and a conical surface 83. As depicted in FIG. 8, the undercut surface 82 extends from one end of the body 20 and is cylindrically shaped. The diameter of the undercut surface 82 is smaller than the diameter of the cylindrical surface 81. The conical surface 83 is located between the cylindrical surface 81 and the undercut surface 82. However, those with skill in the art will appreciate that the outer surface 80 can be fabricated without the conical surface 83 so that the cylindrical surface 81 and the undercut surface 82 abut one another. As shown in FIG. 8, the cylindrical surface 81 abuts the undercut surface 82 forming an outer annular surface 84.

[0039]FIG. 9 depicts the second opening 32 of the embodiment depicted in FIG. 7. The second opening 32 is shown with a second chamfered surface 34. However, those with skill in the art will appreciate that the second opening 32 may be fabricated without the second chamfered surface 34. The second opening 32 is provided with a second annular surface 37.

[0040]FIG. 10 depicts a top view of the second opening 32 of the embodiment depicted in FIG. 7. In FIG. 10, the second annular surface 37 is shown in relation to the first conical surface 42 and the hole 36. As shown in FIG. 10, the hole 36 is concentric relative to the outer surface 80 and the annulus formed by the second annular surface 37.

[0041] Referring now to FIG. 5, the outer surface 80 encloses an inner surface 50. The inner surface 50 includes a plurality of surfaces. The inner surface 50 includes a rounded surface 51 that defines a hole 36. Those skilled in the art will appreciate that the rounded surface 51 need not be rounded, but may be flat. The inner surface 50 includes a first inner conical surface 52 and a second inner conical surface 54, and a first cylindrical surface 53 and a second inner cylindrical surface 55. The first inner conical surface 52 is located adjacent to the rounded surface 51. Adjacent to the first inner conical surface 52 is the first inner cylindrical surface 53. Adjacent to the rounded surface 51 is the first inner conical surface 52. The first inner conical surface 52 is adjacent to the first inner cylindrical surface 53. The first inner cylindrical surface 53 is adjacent to the second inner conical surface 54. The second inner conical surface 54 is adjacent to the second inner cylindrical surface 55.

[0042]FIG. 11 depicts an embodiment of the present invention within another body cooperating with a plurality of inserts. The undercut surface 82 preferably cooperates with another body, such as a lash adjuster body or a valve lifter, to form a leakdown path 93. FIG. 11 depicts an embodiment of the present invention within a lash adjuster body 90; however, those skilled in the art will appreciate that the present invention may be inserted within other bodies, such as roller followers, and valve lifters.

[0043] As shown in FIG. 11, the undercut surface 82 is configured to cooperate with the inner surface 91 of a lash adjuster body 90. The undercut surface 82 and the inner surface 91 of the lash adjuster body 90 cooperate to define a leakdown path 93 for a liquid such as a lubricant.

[0044] The embodiment depicted in FIG. 11 is further provided with a cylindrical surface 81. The cylindrical surface 81 cooperates with the inner surface 91 of the lash adjuster body 90 to provide a first chamber 38. Those skilled in the art will appreciate that the first chamber 38 functions as a high pressure chamber for a liquid, such as a lubricant.

[0045] The second opening 32 is configured to cooperate with a socket 94. The socket 94 is configured to cooperate with a push rod 96. In the embodiment depicted in FIG. 11, the socket 94 preferably functions as a metering socket, such as that disclosed in Applicants' “Metering Socket,” application Ser No. ______, filed on Oct. 18, 2002, a copy of which is attached hereto, the disclosure of which is incorporated herein by reference. As shown in FIG. 11, the socket 94 is provided with a push rod cooperating surface 95. The push rod cooperating surface 95 is configured to function with a push rod 96. Those skilled in the art will appreciate that the push rod 96 cooperates with the rocker arm (not shown) of an internal combustion engine (not shown).

[0046] The socket 94 cooperates with the body 20 of the leakdown plunger to define at least in part a second chamber 39 within the inner surface 50. Those skilled in the art will appreciate that the second chamber 39 may advantageously function as a reservoir for a lubricant. The inner surface 50 of the body 20 functions to increase the quantity of retained fluid in the second chamber 39 through the damming action of the second inner conical surface 54.

[0047] The socket 94 is provided with a plurality of passages that function to fluidly communicate with the cavity 92 of the lash adjuster body 90. In the embodiment depicted in FIG. 11, the socket 94 is provided with a push rod passage 97 and a plunger reservoir passage 98. The plunger reservoir passage 99 functions to fluidly connect the reservoir 39 with the cavity 92 of the lash adjuster body 90. As shown in FIG. 11, the push rod passage 98 functions to fluidly connect the socket 94 and the cavity 92 of the lash adjuster body 90.

[0048] FIGS. 12 to 16 illustrate the presently preferred method of fabricating a leakdown plunger. FIGS. 12 to 16 depict what is known in the art as “slug progressions” that show the fabrication of the present invention from a rod or wire to a finished or near-finished body. In the slug progressions shown herein, pins are shown on the punch side; however, those skilled in the art will appreciate that the pins can be switched to the die side without departing from the scope of the present invention.

[0049] The preferred embodiment is forged with use of a National® 750 parts former machine. However, those skilled in the art will appreciate that other part formers, such as, for example, a Waterbury machine can be used. Those skilled in the art will further appreciate that other forging methods can be used as well.

[0050] The process of forging an embodiment of the present invention begins with a metal wire or metal rod 1000 which is drawn to size. The ends of the wire or rod are squared off. As shown in FIG. 12, this is accomplished through the use of a first punch 1001, a first die 1002, and a first knock out pin 1003.

[0051] After being drawn to size, the wire or rod 1000 is run through a series of dies or extrusions. As depicted in FIG. 13, the fabrication of the second opening 32 and the outer surface 80 is preferably commenced through use of a second punch 1004, a second knock out pin 1005, a first sleeve 1006, and a second die 1007. The second opening 32 is fabricated through use of the second knock out pin 1005 and the first sleeve 1006. The second die 1007 is used to fabricate the outer surface 80. As shown in FIG. 13, the second die 1007 is composed of a second die top 1008 and a second die rear 1009. In the preferred forging process, the second die rear 1009 is used to form the undercut surface 82 and the conical surface 83.

[0052] As depicted in FIG. 14, the first opening 31 is fabricated through use of a third punch 1010. Within the third punch 1010 is a first pin 1011. The third punch 1010 and the first pin 1011 are used to fabricate at least a portion of the annular surface 35. As shown in FIG. 14, it is desirable to preserve the integrity of the outer surface 80 through use of a third die 1012. The third die 1012 is composed of a third die top 1013 and a third die rear 1014. Those skilled in the art will appreciate the desirability of using a third knock out pin 1015 and a second sleeve 1016 to preserve the forging of the second opening.

[0053]FIG. 15 depicts the forging of the inner surface 50. As depicted, the inner surface 50 is forged through use of a punch extrusion pin 1017. Those skilled in the art will appreciate that it is advantageous to preserve the integrity of the first opening 31 and the outer surface 80. This function is accomplished through use of a fourth die 1018 and a fourth knock out pin 1019. A punch stripper sleeve 1020 is used to remove the punch extrusion pin 1017 from the inner surface 50.

[0054] As shown in FIG. 16, the hole 36 is fabricated through use of a piercing punch 1021 and a stripper sleeve 1022. To assure that other forging operations are not affected during the fabrication of the hole 36, a fifth die 1023 is used around the outer surface 80 and a tool insert 1024 is used at the first opening 31.

[0055] FIGS. 17 to 21 illustrate an alternative method of fabricating a leakdown plunger. FIG. 17 depicts a metal wire or metal rod 1000 drawn to size. The ends of the wire or rod 1000 are squared off through the use of a first punch 1025, a first die 1027, and a first knock out pin 1028.

[0056] As depicted in FIG. 18, the fabrication of the first opening 31, the second opening 32, and the outer surface 80 is preferably commenced through use of a punch pin 1029, a first punch stripper sleeve 1030, second knock out pin 1031, a stripper pin 1032, and a second die 1033. The first opening 31 is fabricated through use of the second knock out pin 1031. The stripper pin 1032 is used to remove the second knock out pin 1031 from the first opening 31.

[0057] The second opening 32 is fabricated, at least in part, through the use of the punch pin 1033. A first punch stripper sleeve 1034 is used to remove the punch pin 1033 from the second opening 32. The outer surface 80 is fabricated, at least in part, through the use of a second die 1035. The second die 1035 is composed of a second die top 1036 and a second die rear 1037.

[0058]FIG. 19 depicts the forging of the inner surface 50. As depicted, the inner surface 50 is forged through the use of an extrusion punch 1038. A second punch stripper sleeve 1039 is used to remove the extrusion punch 1038 from the inner surface 50.

[0059] Those skilled in the art will appreciate that it is advantageous to preserve the previous forging of the first opening 31 and the outer surface 80. A third knock out pin 1043 is used to preserve the previous forging operations on the first opening 31. A third die 1040 is used to preserve the previous forging operations on the outer surface 80. As depicted in FIG. 19, the third die 1040 is composed of a third die top 1041 and a third die rear 1042.

[0060] As depicted in FIG. 20, a sizing die 1043 is used in fabricating the second inner conical surface 54 and the second inner cylindrical surface 55. The sizing die 1043 is run along the outer surface 80 from the first opening 31 to the second opening 32. This operation results in metal flowing through to the inner surface 50.

[0061] As shown in FIG. 21, the hole 36 is fabricated through use of a piercing punch 1044 and a stripper sleeve 1045. The stripper sleeve 1045 is used in removing the piercing punch 1044 from the hole 36. To assure that other forging operations are not affected during the fabrication of the hole 36, a fourth die 1046 is used around the outer surface 80 and a tool insert 1047 is used at the first opening 31.

[0062] Those skilled in the art will appreciate that further desirable finishing may be accomplished through machining. For example, an undercut surface 82 may be fabricated and the second opening 32 may be enlarged through machining. Alternatively, as depicted in FIG. 22, a shave punch 1048 may be inserted into the second opening 32 and plow back excess material.

[0063] While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. 

What is claimed is:
 1. A leakdown plunger, comprising: a) a first opening configured to accommdate an insert; b) a second opening configured to cooperate with a socket; c) an outer surface configured for insertion into another body, enclosing an inner surface configured to define a chamber; and d) at least one of the surfaces is fabricated through forging.
 2. A leakdown plunger according to claim 1, wherein at least one of the openings is provided with a chamfered opening.
 3. A leakdown plunger according to claim 1, wherein the inner surface includes a plurality of cylindrical and conical surfaces.
 4. A leakdown plunger according to claim 1, wherein the insert is a valve.
 5. A leakdown plunger according to claim 1, wherein the inner surface includes a conically-shaped surface.
 6. A leakdown plunger according to claim 1, wherein the outer surface includes a plurality of conical and cylindrical surfaces. 